When diarrhea chrysanthemum (anus) especially painful may be fecal stimulation and other physiological factors or anal fissure, hemorrhoids and other pathological factors lead to. 1. Physiological factors: diarrhea will pull out a lot of water and electrolytes, which electrolytes will stimulate the perianal area, triggering a special pain in the anus. 2. Pathologic factors: (1) anal fissure: diarrhea, can cause perianal muscles too hard to trigger tearing, anal fissure, the occurrence of anal special pain. (2) hemorrhoids: diarrhea, more often lead to increased pressure in the anus, resulting in blood flow to the perianal area, stimulating hemorrhoids congestion and recurrence, the anus is particularly painful. There may be other reasons for the special pain in the anus when you have diarrhea, it is recommended to go to the hospital in a timely manner, under the guidance of the doctor to improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment.